The present invention relates, inter alia, to polyspecificity reagents, methods of making the same, and methods of using the same in, inter alia, the selection, screening, enrichment, and identification of non-polyspecific, and thus developable, polypeptides.

The present invention relates, inter alia, to polyspecificity reagents, methods of making the same, and methods of using the same in, inter alia, the selection, screening, enrichment, and identification of non-polyspecific, and thus developable, polypeptides.

The present invention overcomes the inadequacies inherent in the known methods for generating libraries of antibody-encoding polynucleotides by specifically designing the libraries with directed sequence and length diversity. The libraries are designed to reflect the preimmune repertoire naturally created by the human immune system, with or without DH segments derived from other species, and are based on rational design informed by examination of publicly available databases of antibody sequences.

Multivalent antibody analogs that co-engage at least two different antigens or epitopes (also referred to targets, used interchangeably throughout), are provided, as well as methods for their production and use.

The present invention overcomes the inadequacies inherent in the known methods for generating libraries of antibody-encoding polynucleotides by specifically designing the libraries with directed sequence and length diversity. The libraries are designed to reflect the preimmune repertoire naturally created by the human immune system and are based on rational design informed by examination of publicly available databases of human antibody sequences.